In order to investigate the aerodynamic and aeroacoustic characteristics of objects, said objects or true-to-scale three-dimensional models of the objects to be investigated are placed in a wind tunnel or flow tunnel. For example, models of aircraft or other vehicles are arranged in a flow tunnel and exposed to a flow of a fluid, for example a flow of air. Apart from investigating models of vehicles, a flow tunnel can also be used for investigating buildings. In this respect, a three-dimensional model of a building, for example a multi-storey building or a bridge, is arranged in the wind tunnel and exposed to an air flow.
Due to the restricted diameter of a flow tunnel, it is rare for objects to be investigated in their original size in the flow tunnel. For this reason, true-to-scale, three-dimensional models are usually made of large objects and arranged in the flow tunnel to investigate the flow behaviour of the object.
For bodies, in particular aircraft, it is important when investigating the aerodynamic behaviour thereof to detect the forces which act on the body in order to be able to verify characteristics of the body or to be able to make improvements to components or to the structure of the body.
In conventional measuring systems, the forces acting on the body are measured statically, for example by means of so-called wind tunnel balances. In measuring systems of this type, the force is measured directly by the wind tunnel balances, averages of the forces acting on the body being measured by the wind tunnel balance.
These conventional systems for determining a force acting on a body suffer from various disadvantages. On the one hand, the wind tunnel balance only measures averages of the force acting on the body and does not measure any time behaviour, i.e. only a static force measurement is made, not a dynamic force measurement. Furthermore, a conventional system for determining a force using a wind tunnel balance is not suitable for some components or parts of a body. To measure forces which act on a rotating body of an aircraft, for example on a propeller, a wind tunnel balance has to be fitted to the rotating component or rotating part. This can only be achieved with considerable technical complexity. Furthermore, the centrifugal forces which arise during rotation falsify the measurement result.